Implementation and Operational Research: Cost-Effectiveness of Antiretroviral Therapy and Isoniazid Prophylaxis to Reduce Tuberculosis and Death in People Living With HIV in Botswana.

OBJECTIVE

In Botswana, a 36-month course of isoniazid treatment of latent tuberculosis (TB) infection [isoniazid preventive therapy (IPT)] was superior to 6-month IPT in reducing TB and death in persons living with HIV (PLHIV), having positive tuberculin skin tests (TSTs) but not in those with negative TST. We examined the cost-effectiveness of IPT in Botswana, where antiretroviral therapy (ART) is widely available.

DESIGN

Using a decision-analytic model, we determined the incremental cost-effectiveness of strategies for reducing TB and death in 10,000 PLHIV over 36 months.

METHODS

IPT for 6 months and provision of ART if CD4 lymphocyte count <250 cells per microliter (2011 Botswana policy) was compared with 6 alternative strategies that varied the use of IPT, TST, and ART for CD4 count thresholds, including CD4 <350 and <500 cells per microliter.

RESULTS

Botswana policy, 2011 was dominated by most other strategies. IPT of 36 months for TST-positive PLHIV with ART for CD4 <250 cells per microliter resulted in 120 fewer TB cases for an additional cost of $1612 per case averted and resulted in 80 fewer deaths for an additional $2418 per death averted compared with provision of 6-month IPT to TST-positive PLHIV who received ART for CD4 <250 cells per microliter, the next most effective strategy. Alternative strategies offered lower incremental effectiveness at higher cost. These findings remained consistent in sensitivity analyses.

CONCLUSIONS

A strategy of treating PLHIV who have positive TST with 36-month IPT is more cost effective for reducing both TB and death compared with providing IPT without a TST, providing only 6-month IPT, or expanding ART eligibility without IPT.